As a liquid droplet discharge apparatus, there have been known an inkjet printer having a recording head in which a plurality of nozzles discharging liquid droplets of ink is arranged in a nozzle array. While reciprocating the recording head in a main scanning direction, the printer discharges the liquid droplets of ink to a recording medium moving in a sub-scanning, so as to perform a recording operation. In the printer, a plurality of lines is recorded by scanning of one time. That is, the recording is performed in a recording area corresponding to a width of the nozzle array every main scanning.
When recording a deep color image on a recording medium on which ink easily blurs, such as normal sheet, the blur is conspicuous at a dry edge of the recording area, around which the ink is not colored. The blur overlaps at a boundary part of the two recording areas, so that a black line may occur.
The occurrence of the black line can be prevented by adjusting an amount of relative movement of the recording head and the recording medium in the sub-scanning direction. That is, an interval between the recording areas is increased every main scanning, so that it is possible to prevent the overlapping of the blur and to prevent the black line from occurring. However, when a light color image is recorded at the adjusted state, an amount of the ink is small, so that the blur is also small and a white line is generated between the recording areas.
If an amount of the movement of the sub-scanning every recording area were adjusted, in correspondence to an image to be recorded, it could be possible to prevent the black line or white line. However, the control thereof is complicated.
Thus, there have been proposed a technology in which a liquid droplet discharge head having a nozzle array having a plurality of large nozzles arranged at a central part and a nozzle array having a plurality of small nozzles arranged at an end portion is used. According to this related-art technology, when discharging liquid droplets, the small nozzles discharge the liquid droplets at a boundary part of the recording area by the large nozzles, so that the occurrence of the line at the boundary part may be reduced.